Vehicle collision avoidance system with enhanced pedestrian avoidance

ABSTRACT

A collision avoidance system of a vehicle includes a sensor configured to be disposed at a vehicle for sensing exterior and forwardly of the vehicle. A processor is operable to process sensor data captured by the sensor to determine the presence of a pedestrian ahead of the vehicle and at or moving towards a path of travel of the vehicle. The processor determines a time to collision based on a determined distance to the pedestrian and determined speed of the pedestrian and speed of the vehicle. The collision avoidance system is operable to generate an alert to the driver of the vehicle at a threshold time before the determined collision with the pedestrian. Responsive to a parameter, the collision avoidance system adjusts the threshold time to generate the alert at an earlier time.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to U.S. provisional applications,Ser. No. 62/129,285, filed Mar. 6, 2015, and Ser. No. 62/051,446, filedSep. 17, 2014, which are hereby incorporated herein by reference intheir entireties.

FIELD OF THE INVENTION

The present invention relates generally to a collision avoidance systemfor a vehicle and, more particularly, to a collision avoidance systemthat detects pedestrians in or approaching.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties.

SUMMARY OF THE INVENTION

The present invention provides a collision avoidance system or visionsystem or imaging system for a vehicle that utilizes one or moresensors, such as one or more cameras (preferably one or more CMOScameras) to sense regions exterior (such as forward) of the vehicleand/or to capture image data representative of images exterior of thevehicle, and provides a pedestrian collision warning system that isoperable to generate an alert or warning to a driver of the vehicleand/or to control the brake system of the vehicle responsive to adetermination that the vehicle may collide with a pedestrian approachingthe path of travel of the vehicle ahead of (or behind) the vehicle. Thesystem may determine a baseline time to collision (TTC) based on vehiclespeed and pedestrian speed and distance between the vehicle andpedestrian, and the system adjusts the TTC responsive to variousparameters, including vehicle parameters (pertaining to traction orbraking ability of the vehicle at that time), environmental parameters,location parameters (such as the location of the vehicle being at ornear where a pedestrian is more likely to be found),condition/time/place parameters (such as the location of the vehiclebeing at or near a location and at a particular time where a pedestrianis more likely to be found at that location) and/or driver parameters(attentiveness of driver, distractions and/or the like). For example,when the vehicle is at a location near a bus stop when the bus is at thebus stop (thus a high likelihood that pedestrians will be present), thesystem may increase the sensitivity and provide an earlier warning tothe driver of the vehicle or may control the vehicle (such as apply thevehicle brakes) at an earlier time, when it is determined that apedestrian may be moving in or towards the path of travel of thevehicle.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates cameras in accordance with the present invention;

FIG. 2 is a schematic showing a vehicle approaching a path of apedestrian;

FIG. 3 is another schematic showing a vehicle approaching a path of apedestrian;

FIG. 4 is another schematic showing a vehicle approaching a path of apedestrian, showing various trajectories of the pedestrian relative tothe vehicle depending on the speed of the pedestrian and the speed ofthe vehicle;

FIG. 5 is a schematic showing a vehicle approaching a path of apedestrian;

FIG. 6 is another schematic showing a vehicle approaching a path of apedestrian, showing distances for warnings depending on variousparameters;

FIG. 7 is another schematic showing a vehicle approaching a path of apedestrian;

FIG. 8 shows cases A, B and C with a pedestrian walking with a constantspeed into the path of travel of a vehicle with constant speed, startingfrom different starting points and by that being at different positionswhen the vehicle closes;

FIG. 9 shows further details of the case A of FIG. 8;

FIG. 10 shows a distance over time diagram (which implies the speed),from which it is apparent that an early soft braking (upon sufficientdetection of a hazard) may be sufficient for winning the time whichallows an inattentive pedestrian to escape or avoid being hit by thevehicle; and

FIG. 11 shows further details of the case C of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide a top down or bird's eye orsurround view display and may provide a displayed image that isrepresentative of the subject vehicle, and optionally with the displayedimage being customized to at least partially correspond to the actualsubject vehicle.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes at least one exterior facing imaging sensor or camera,such as a rearward facing imaging sensor or camera 14 a (and the systemmay optionally include multiple exterior facing imaging sensors orcameras, such as a forwardly facing camera 14 b at the front (or at thewindshield) of the vehicle, and a sidewardly/rearwardly facing camera 14c, 14 d at respective sides of the vehicle), which captures imagesexterior of the vehicle, with the camera having a lens for focusingimages at or onto an imaging array or imaging plane or imager of thecamera (FIG. 1). The vision system 12 includes a control or electroniccontrol unit (ECU) or processor 18 that is operable to process imagedata captured by the cameras and may provide displayed images at adisplay device 16 for viewing by the driver of the vehicle (althoughshown in FIG. 1 as being part of or incorporated in or at an interiorrearview mirror assembly 20 of the vehicle, the control and/or thedisplay device may be disposed elsewhere at or in the vehicle). The datatransfer or signal communication from the camera to the ECU may compriseany suitable data or communication link, such as a vehicle network busor the like of the equipped vehicle.

ASPECSS (Assessment methodologies for forward looking IntegratedPedestrian and further extension to Cyclist Safety Systems) is a projectto develop harmonized test and assessment procedures for forward lookingintegrated pedestrian safety systems. See, for example,‘ASPECSS-D1.1-FINAL-Scenariosweighting-BASt-2013-02-17-PUBLIC’, which ishereby incorporated herein by reference in its entirety.

As disclosed in the ASPECSS document (incorporated above), it may bejustified to adjust the size of a safety zone depending on thepedestrian's walking speed. Therefore, the quantity safe lateraltime-gap SLT is introduced. The conversion of safe lateral distance(SLD) to safe lateral time (SLT) is:

${{SLT} = \frac{SLD}{v_{Ped}}};$

where V_(Ped) is the speed component of a pedestrian lateral to the wayan ego-vehicle is heading. This is linear vector algebra. ASPECSS showsthat more distant pedestrians have to be reflected when they areapproaching faster and less distant when they are approaching slower.

ASPECSS describes a safety zone which expands in a cone shape in frontof the vehicle. The faster a potential endangered pedestrian is, themore time he or she may have to walk in front of the approachingvehicle.

FIG. 2 shows a diagram of the basic TTC calculation. The calculationassumes a contact point in the center of the vehicle, a constant vehiclespeed and a constant speed of the pedestrian. In FIG. 3, the remainingdistance to the collision point is calculated out of vehicle speed andTTC. The corridor (B) in which a pedestrian (or other vulnerable roaduser or VRU) with a constant approaching speed may be hit in is shown inFIGS. 4 and 5. Thus, if the pedestrian will be hit (at point B in FIG. 4or to either side of B and within the determined path of travelcorridor), the system may warn the driver and/or the pedestrian and/ormay apply the vehicle brakes. Also shown in FIG. 4 is the case where thepedestrian walks faster so he or she passes the vehicle corridor beforethe vehicle arrives at his or her location (see A in FIG. 4). In casethe pedestrian walks slower he or she will not reach the vehiclecorridor before the vehicle arrives at his or her location (see C inFIG. 4).

The diagrams in FIG. 6 shows different scenarios which apply dependingon whether the pedestrian is walking faster or slower (or if the vehicleis traveling faster or slower), one starting from a more distantposition than the other for arriving at the collision point at the samemoment. The examples show that, with the same detection cone angle, afaster pedestrian starting from a higher distant position gets detectedlater, and by that the reaction time for him or her is shorter. FIG. 7shows in which way the detection cone angle should be adapted dependingon the vehicle speed for capturing a fast approaching pedestrian in timefor safe braking of the vehicle. For example, and in accordance with thepresent invention, the vehicle's corridor may be effectively widened(reducing the determined time to collision) for a faster movingpedestrian (or responsive to other parameters as discussed below), suchthat the distance at which the system may act for both the slower movingpedestrian and the faster moving pedestrian is about the same. Thus,since the system already measures the lateral position of the pedestrianrelative to the vehicle, the speed of the pedestrian can be determinedand used to widen the corridor (shorten the determined TTC) for thepedestrian position at which the system determines that the vehicle andpedestrian may be on course for a collision. FIGS. 8 and 9 show that notthe center but the far edges of the vehicle are relevant when it comesto barely hitting or missing a pedestrian walking in the way of travelof an approaching vehicle.

Since semi-automated abrupt accelerating may be disturbing to a driverfor passing an approaching pedestrian before he or she may be able toenter the path of travel of the approaching vehicle, only decelerationmay be acceptable as an automated measure. The case A in FIG. 9 showsthat, for allowing an inattentive pedestrian to exit the path of travelof the own approaching vehicle, a small delay may be sufficient. FIG. 10shows a distance over time diagram (which implies the speed), from whichit is apparent that an early soft braking (upon sufficient detection ofa hazard) may be sufficient for gaining sufficient time which allows aninattentive pedestrian to escape or avoid collision. This soft brakingearly may be much safer for pedestrians and more comfortable to vehicleoccupants as compared to waiting to the last moment and then applying orengaging full braking to avoid or rescue an endangered pedestrian. Ascan be seen in FIG. 11, since the time to engage measures is comparablyhigh, the vehicle may flash its lights or may acoustically signal to thepedestrian. When this does not help, it may engage forward collisionwarning (FCW) and/or automated emergency braking (AEB) of the vehicle.

As another aspect of the invention, for implementation in activepedestrian collision avoidance or collision warning systems, it ispreferred to engage actions stepwise depending on the remaining time tocollision (TTC). Typically, in a first stage actuation or warning levelsbecome elevated. Audible, visual and/or haptic measures may be actuatedto draw the driver's attention to a potential collision endangeredpedestrian (assuming the pedestrian continues approaching the drivingpath of the vehicle). The systems are often not developed enough toavoid a collision by steering (in combination with braking), by thatthese are meant to brake only. In another higher actuation or warninglevels when the TTC is shorter, the system may prefill the brakepressure and may actively lower the torque demand of the engine. Thewarnings may be switched to become more obtrusive such as like soundinga beep and warning lights may flicker. At a TTC when a collision seemsto become unavoidable in case of not braking the vehicle may start fullbraking of the vehicle.

While the last stages of actuation or warning levels may be reached veryseldom, the lower levels may be reached quite often. To limit or avoiddisturbing the driver too often with false positive or obviously easy toavoid conflict warnings but to brake sufficiently when it is necessaryfor pedestrians'safety, the OEMs aspire to optimize the parameters whichlead to the early warning or warning levels. This is done by parameters.

There is a base TTC at which a system may actuate early warnings. Mostof the parameters lead to earlier warnings which equates to a higher TTCvalue. For simplifying the concept some OEMs quantize the parameters inlevels which lead to a fixed value of time which has to be added to thebase TTC (from a baseline time). Any count of levels may be used. TheOEM typically use three levels, such as a level for ‘wiper status.’ Alevel of 3 (such as engaged in heavy rain) leads to an addition of 0.6seconds to the TTC, while a level of 1 (such as ‘Interval,’ engaged inslight rain) leads to an addition of 0.2 seconds to the TTC.

Known other parameters include:

-   -   Headlight condition    -   Steering Wheel angle    -   Yaw rate    -   Count of pedestrians    -   Pedestrian size (such for distinguishing children from        adults—children may be more at risk)

The system of the present invention uses additional vehicle imminentparameters in determining an adjustment of the TTC (where the system mayreduce the alert time if the system determines excessive tire wear orexcessive brake temperature or wear or the like, where a time to stopthe vehicle may be increased), such as:

-   -   Tire wear    -   Tire pressure    -   Tire age    -   Vehicle load (or common weight)    -   Brake temperature    -   Brake wear (effectiveness)

Additionally, the system of the present invention may also takeenvironmental and/or temporal parameters (where the system may reducethe alert time if conditions are such that a time to stop the vehiclemay be increased) into account such as:

-   -   Ambient Temperature    -   Weather conditions    -   Time of day    -   Date or season

A more sophisticated system may be able to detect ground or road orvehicle tire-road interface conditions. This may done by assessing thetire slip (where the system may reduce the alert time if conditions aresuch that a time to stop the vehicle may be increased). Such informationmay be generated by the ABS and TCS (traction control system) of thevehicle. Alternatively, or additionally, the system may assume a roadcondition by the weather forecast or may receive the road condition froma data server, specific to the position the vehicle is at that moment.

The geographical location or position may come from a navigation systemwith GPS. Additionally or alternatively the system may have parametersaccording a position dependent context information. The vehicle may usethe inherent present information or may receive information from acontext server. For example, at times when the navigation systemindicates the system is approaching a school, the context parameter mayadd a higher value to the base TTC than when driving on a highway (whereno pedestrian are to be expected normally).

Additional contexts at which increased or decreased parameter levels maybe engaged may pertain to the current geographical location of thevehicle (where the system may reduce the alert time if the geographicallocation of the vehicle is at or near a location where more pedestriansare expected to be), and may include, for example:

-   -   In city    -   Out of city    -   In living area    -   On highway    -   Off road    -   Close to a bus stop    -   Close to a train station    -   Within a pedestrian walking zone    -   On a play street

Some contexts may be engaged in combination, such as condition, time andplace in combination (where the timing of an event that occurs at aparticular location at a particular time may be considered when thevehicle is determined to be at or near a particular location at or nearthe time for an event at that location, such that the alert time may bereduced if the system determines that the vehicle is at or near such alocation at such a time) such as:

-   -   Close to a stadium when a game just ended (position, game        schedule and time)    -   Close to a bus stop with the bus scheduled at that time        (position, bus schedule and time)    -   Approaching a traffic jam that is at a full stop (people may        exit their cars) (road type and traffic condition)    -   Fire alert in a building close by (exceptional event and        position)

There may be off line data involved such as the map information or thebus schedule as well as online data such as the fire alert event.Sophisticated systems may keep the bus schedule updated online, by thata bus which is a minute delayed can be reflected in the TTC parameterscorrectly when the bus is actually present (not when it was scheduledinstead).

As another aspect of the present invention, the system may also take thecondition of the driver and or driver distractions into account as aparameter (where the system may reduce the alert time if it isdetermined that the driver may be distracted or inattentive) such as:

-   -   Attention and or drowsiness level of the driver (detected by an        eye tracker and or by monitoring gas pedal and steering wheel        actuations)    -   Volume of music in the vehicle    -   Driver is on a cellphone (hands free/not hands free)    -   Driver is drunk or otherwise impaired    -   Driver is beginner    -   Driver is an elderly driver    -   Driver is alone in the vehicle vs. accompanied by one or more        passengers in the vehicle

Optionally, the same procedure may be used accordingly andsimultaneously for setting (increasing) the parameters of “Presentposition of the Pedestrian.”

This procedure may also be used for TTC parameters of cyclists,motorcyclists, rickshaws, horse riders (vulnerable road users or VRU) orother vehicles or animals or other (potentially moving) obstacles suchas dropped cargo (rolling around), rolling bushes or toys (e.g., balls,RC or autonomous crafts or drones); it means all AEB features can takeadvantage of the adjustment of the adaption of the thresholds forwarnings or braking maneuvers.

Thus, the system of the present invention is operable to adjust orweight the processing of data associated with the vehicle travelingalong a road to optimize the system's ability to warn against or avoidcollision with a pedestrian. The system may increase the sensitivity ofthe alert (to effectively widen the vehicle path corridor in FIG. 7) toprovide the alert (or to control the vehicle brake system or the like)earlier (by reducing a time to alert) responsive to parameter that areindicative of an increased likelihood that a pedestrian may be presentin or near the path of travel of the vehicle and/or that are indicativeof poor driving conditions (such as rain or snow or poor traction) thatmay require additional time and distance to stop the vehicle when thebrakes are applied. The system is thus responsive to vehicle parameters(pertaining to traction or braking ability of the vehicle at that time),environmental parameters, location parameters (such as the location ofthe vehicle being at or near where a pedestrian is more likely to befound), condition/time/place parameters (such as the location of thevehicle being at or near a location and at a particular time where apedestrian is more likely to be found at that location) and/or driverparameters (attentiveness of driver, distractions and/or the like), andadjusts the vehicle control or warning time and/or intensity responsiveto such parameters. For example, when the vehicle is at a location neara bus stop when the bus is at the bus stop (thus a high likelihood thatpedestrians will be present), the system may increase the sensitivity(and reduce the time to alert) and provide an earlier warning to thedriver of the vehicle or may control the vehicle (such as apply thevehicle brakes) at an earlier time, when it is determined that apedestrian may be moving in or towards the path of travel of thevehicle.

Thus, the system of the present invention uses vehicle inherentparameters to influence the TTC warning time (at which the driver willbe alerted to a potential collision with a pedestrian). The system mayalso or otherwise use environmental parameters and may generate contextinformation from several input conditions, which influence the variousparameters and the TTC warning time. The system may utilize one or morecameras of the vehicle to assist in determining the presence ofpedestrians and may be responsive to an output of a GPS system of thevehicle (that indicates the current geographical location of thevehicle) and/or may be responsive to an external service provider orcommunication system (that may provide data pertaining to bus schedulesor real time bus locations and/or school crossing information and/orweather details and/or the like). The system may be responsive to thevarious parameters (as provided or determined or as adjusted in responseto other inputs or data) to determine a time at which the system maywarn the driver of the vehicle of a potential hazard (collision withpedestrian) as the vehicle is driven along a road.

Thus, the system may initially determine a potential hazard or collisionwith a pedestrian and generate an alert to the driver of the vehiclethat the hazardous condition has been determined. If the pedestriancontinues on his or her path and the driver of the vehicle does notalter the vehicle's path or speed, the system may then control thevehicle and/or generate a pedestrian alert to alert the pedestrian ofthe potentially hazardous condition. For example, responsive to aninitial determination that a detected pedestrian is moving towards thepath of travel of the vehicle, the system may generate a pedestrianalert (such as actuating the vehicle's horn or flashing the vehicle'sheadlights) to alert the pedestrian of a potential hazard. If thepedestrian does not alter course, the system may (if a determination ismade that the vehicle may collide with the pedestrian) apply the vehiclebrakes to slow down or stop the vehicle before arriving at the locationwhere the pedestrian crosses the vehicle's path. This may be done afterthe processor determines a time to collision based on a determineddistance to the pedestrian and determined speed of the pedestrian andspeed of the vehicle, and after the collision avoidance system generatesan alert to the driver of the vehicle at a threshold time before thedetermined collision with the pedestrian.

The collision avoidance system may be operable to apply the brakes ofthe vehicle to avoid collision with a determined pedestrian. Optionally,the system may adjust the degree of braking responsive to the predictedlocation of the pedestrian at the time that the vehicle arrives at thepedestrian's path. For example, the system may gently or lightly applythe brakes to slow the vehicle's speed responsive to a determinationthat the pedestrian will be exiting the path of travel of the vehicletowards the end of the determined time to collision (i.e., thepedestrian is fully or almost fully across the vehicle path by the timethe vehicle arrives at the pedestrian's path). Optionally, the collisionavoidance system may apply the brakes of the vehicle to stop the vehicleresponsive to a determination that the pedestrian will be entering thepath of travel of the vehicle towards the end of the determined time tocollision (i.e., the pedestrian will likely be in the path of travel ofthe vehicle at the time that the vehicle arrives at the pedestrian'spath). Optionally, the collision avoidance system may generate apedestrian alert to the pedestrian responsive to a determination thatthe pedestrian will be entering the path of travel of the vehicletowards the end of the determined time to collision (i.e., at or beforethe time at which the vehicle arrives at the pedestrian's path).

The camera or sensor may comprise any suitable camera or sensor.Optionally, the camera may comprise a “smart camera” that includes theimaging sensor array and associated circuitry and image processingcircuitry and electrical connectors and the like as part of a cameramodule, such as by utilizing aspects of the vision systems described inInternational Publication Nos. WO 2013/081984 and/or WO 2013/081985,which are hereby incorporated herein by reference in their entireties.

The system includes an image processor operable to process image datacaptured by the camera or cameras, such as for detecting objects orother vehicles or pedestrians or the like in the field of view of one ormore of the cameras. For example, the image processor may comprise anEyeQ2 or EyeQ3 image processing chip available from Mobileye VisionTechnologies Ltd. of Jerusalem, Israel, and may include object detectionsoftware (such as the types described in U.S. Pat. Nos. 7,855,755;7,720,580 and/or 7,038,577, which are hereby incorporated herein byreference in their entireties), and may analyze image data to detectvehicles and/or other objects. Responsive to such image processing, andwhen an object or other vehicle is detected, the system may generate analert to the driver of the vehicle and/or may generate an overlay at thedisplayed image to highlight or enhance display of the detected objector vehicle, in order to enhance the driver's awareness of the detectedobject or vehicle or hazardous condition during a driving maneuver ofthe equipped vehicle.

The vehicle may include any type of sensor or sensors, such as imagingsensors or radar sensors or lidar sensors or ladar sensors or ultrasonicsensors or the like. The imaging sensor or camera may capture image datafor image processing and may comprise any suitable camera or sensingdevice, such as, for example, a two dimensional array of a plurality ofphotosensor elements arranged in at least 640 columns and 480 rows (atleast a 640×480 imaging array, such as a megapixel imaging array or thelike), with a respective lens focusing images onto respective portionsof the array. The photosensor array may comprise a plurality ofphotosensor elements arranged in a photosensor array having rows andcolumns. Preferably, the imaging array has at least 300,000 photosensorelements or pixels, more preferably at least 500,000 photosensorelements or pixels and more preferably at least 1 million photosensorelements or pixels. The imaging array may capture color image data, suchas via spectral filtering at the array, such as via an RGB (red, greenand blue) filter or via a red/red complement filter or such as via anRCC (red, clear, clear) filter or the like. The logic and controlcircuit of the imaging sensor may function in any known manner, and theimage processing and algorithmic processing may comprise any suitablemeans for processing the images and/or image data.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 8,694,224;7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331; 6,222,447;6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202; 6,201,642;6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452; 6,822,563;6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935; 6,636,258;7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466;7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287; 5,929,786 and/or5,786,772, which are all hereby incorporated herein by reference intheir entireties. The system may communicate with other communicationsystems via any suitable means, such as by utilizing aspects of thesystems described in International Publication Nos. WO/2010/144900; WO2013/043661 and/or WO 2013/081985, and/or U.S. Publication No.US-2012-0062743, which are hereby incorporated herein by reference intheir entireties.

Optionally, the vision system may include a display for displayingimages captured by one or more of the imaging sensors for viewing by thedriver of the vehicle while the driver is normally operating thevehicle. Optionally, for example, the vision system may include a videodisplay device disposed at or in the interior rearview mirror assemblyof the vehicle, such as by utilizing aspects of the video mirror displaysystems described in U.S. Pat. No. 6,690,268 and/or U.S. Publication No.US-2012-0162427, which are hereby incorporated herein by reference intheir entireties. The video mirror display may comprise any suitabledevices and systems and optionally may utilize aspects of the compassdisplay systems described in U.S. Pat. Nos. 7,370,983; 7,329,013;7,308,341; 7,289,037; 7,249,860; 7,004,593; 4,546,551; 5,699,044;4,953,305; 5,576,687; 5,632,092; 5,677,851; 5,708,410; 5,737,226;5,802,727; 5,878,370; 6,087,953; 6,173,508; 6,222,460; 6,513,252 and/or6,642,851, and/or European patent application, published Oct. 11, 2000under Publication No. EP 0 1043566, and/or U.S. Publication No.US-2006-0061008, which are all hereby incorporated herein by referencein their entireties. Optionally, the video mirror display screen ordevice may be operable to display images captured by a rearward viewingcamera of the vehicle during a reversing maneuver of the vehicle (suchas responsive to the vehicle gear actuator being placed in a reversegear position or the like) to assist the driver in backing up thevehicle, and optionally may be operable to display the compass headingor directional heading character or icon when the vehicle is notundertaking a reversing maneuver, such as when the vehicle is beingdriven in a forward direction along a road (such as by utilizing aspectsof the display system described in International Publication No. WO2012/051500, which is hereby incorporated herein by reference in itsentirety).

Optionally, the vision system (utilizing the forward facing camera and arearward facing camera and other cameras disposed at the vehicle withexterior fields of view) may be part of or may provide a display of atop-down view or birds-eye view system of the vehicle or a surround viewat the vehicle, such as by utilizing aspects of the vision systemsdescribed in International Publication Nos. WO 2010/099416; WO2011/028686; WO 2012/075250; WO 2013/019795; WO 2012/075250; WO2012/145822; WO 2013/081985; WO 2013/086249 and/or WO 2013/109869,and/or U.S. Publication No. US-2012-0162427, which are herebyincorporated herein by reference in their entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

1. A collision avoidance system of a vehicle, said collision avoidancesystem comprising: a sensor configured to be disposed at a vehicle forsensing exterior and forwardly of the vehicle; a processor operable toprocess sensor data captured by said sensor to determine the presence ofa pedestrian ahead of the vehicle and at or moving towards a path oftravel of the vehicle, wherein said processor determines a distance tothe determined pedestrian and a moving speed of the determinedpedestrian; wherein said processor determines a time to collision basedon a determined distance to the pedestrian and determined speed of thepedestrian and speed of the vehicle; wherein said collision avoidancesystem is operable to generate an alert to the driver of the vehicle ata threshold time before the determined time to collision with thepedestrian; wherein, responsive to a parameter, said collision avoidancesystem adjusts the threshold time to generate the alert at an earliertime; and wherein said parameter comprises at least one parameterselected from the group consisting of (i) a vehicle parameter pertainingto the current traction of the vehicle, (ii) an environment parameterpertaining to the environment in which the vehicle is traveling, (iii) alocation parameter pertaining to the geographical current location ofthe vehicle, (iv) a location and time parameter pertaining to thecurrent geographical location of the vehicle and a particular event timeassociated with that location and (v) a driver attentiveness parameterpertaining to a determined attentiveness of the driver of the vehicle.2. The collision avoidance system of claim 1, wherein said parametercomprises a vehicle parameter pertaining to the current traction of thevehicle.
 3. The collision avoidance system of claim 2, wherein saidvehicle parameter includes at least one of tire wear, tire pressure,tire age, vehicle load, brake temperature, brake wear and tire slip. 4.The collision avoidance system of claim 1, wherein said parametercomprises an environment parameter pertaining to the environment inwhich the vehicle is traveling.
 5. The collision avoidance system ofclaim 4, wherein said environment parameter includes at least oneparameter selected from the group consisting of (i) an ambienttemperature at the vehicle, (ii) a weather condition, (iii) the currentdate and (iv) the current season.
 6. The collision avoidance system ofclaim 1, wherein said parameter comprises a location parameterpertaining to the current geographical location of the vehicle.
 7. Thecollision avoidance system of claim 6, wherein said location parameterincludes at least one parameter pertaining to the vehicle being at alocation selected from the group consisting of (i) a highway location,(ii) an in city location, (iii) an out of city location, (iv) aresidential location, (v) an off road location, (vi) a location close toa bus stop, (vii) a location close to a train station, (viii) a locationwithin a pedestrian walking zone and (ix) a location at a play street.8. The collision avoidance system of claim 1, wherein said parametercomprises a location and time parameter pertaining to the currentgeographical location of the vehicle and a particular event timeassociated with that location.
 9. The collision avoidance system ofclaim 8, wherein said location and time parameter includes at least oneparameter selected from the group consisting of (i) the vehicle is closeto a stadium when an event just ended, (ii) the vehicle is close to abus stop with the bus scheduled at that time, (iii) the vehicle isapproaching a traffic jam that is at a full stop at that time and (iv) afire alert in a building near to the current geographical location ofthe vehicle.
 10. The collision avoidance system of claim 1, wherein saidparameter comprises a driver attentiveness parameter pertaining to adetermined attentiveness of the driver of the vehicle.
 11. The collisionavoidance system of claim 10, wherein said driver attentivenessparameter includes at least one parameter selected from the groupconsisting of (i) a determined attention level of the driver of thevehicle, (ii) a drowsiness level of the driver of the vehicle, (iii) avolume of music in the vehicle, (iv) a determination that the driver isusing a cellphone in the vehicle and (v) a determination of at least onepassenger in the vehicle.
 12. The collision avoidance system of claim 1,wherein said collision avoidance system is operable to apply the brakesof the vehicle to reduce the vehicle speed responsive to a determinationthat the pedestrian will be exiting the path of travel of the vehicletowards the end of the determined time to collision.
 13. The collisionavoidance system of claim 1, wherein said collision avoidance system isoperable to apply the brakes of the vehicle to stop the vehicleresponsive to a determination that the pedestrian will be entering thepath of travel of the vehicle towards the end of the determined time tocollision.
 14. The collision avoidance system of claim 1, wherein saidcollision avoidance system is operable to generate a pedestrian alert tothe pedestrian responsive to a determination that the pedestrian will beentering the path of travel of the vehicle towards the end of thedetermined time to collision.
 15. The collision avoidance system ofclaim 1, wherein said sensor comprises a camera operable to captureimage data and wherein said processor comprises an image processoroperable to process captured image data.
 16. The collision avoidancesystem of claim 15, wherein said camera comprises a pixelated imagingarray having a plurality of photosensing elements.
 17. A collisionavoidance system of a vehicle, said collision avoidance systemcomprising: a camera configured to be disposed at a vehicle so as tohave a field of view exterior and forwardly of the vehicle, said cameracapturing image data; wherein said camera comprises a pixelated imagingarray having a plurality of photosensing elements; an image processoroperable to process image data captured by said camera to determine thepresence of a pedestrian ahead of the vehicle and at or moving towards apath of travel of the vehicle, wherein said image processor determines adistance to the determined pedestrian and a moving speed of thedetermined pedestrian; wherein said image processor determines a time tocollision based on a determined distance to the pedestrian anddetermined speed of the pedestrian and speed of the vehicle; whereinsaid collision avoidance system is operable to generate an alert to thedriver of the vehicle at a threshold time before the determinedcollision with the pedestrian; wherein, responsive to a parameter, saidcollision avoidance system adjusts the threshold time to generate thealert at an earlier time; wherein said parameter comprises at least oneparameter selected from the group consisting of (i) a vehicle parameterpertaining to the current traction of the vehicle, (ii) an environmentparameter pertaining to the environment in which the vehicle istraveling, (iii) a location parameter pertaining to the geographicalcurrent location of the vehicle, (iv) a location and time parameterpertaining to the current geographical location of the vehicle and aparticular event time associated with that location and (v) a driverattentiveness parameter pertaining to a determined attentiveness of thedriver of the vehicle; and wherein said collision avoidance system isoperable to apply the brakes of the vehicle to reduce the vehicle speedresponsive to a determination that the pedestrian will be exiting thepath of travel of the vehicle towards the end of the determined time tocollision.
 18. The collision avoidance system of claim 17, wherein saidparameter comprises a location and time parameter pertaining to thecurrent geographical location of the vehicle and a particular event timeassociated with that location, and wherein said location and timeparameter includes at least one parameter selected from the groupconsisting of (i) the vehicle is close to a stadium when a game justended, (ii) the vehicle is close to a bus stop with the bus scheduled atthat time, (iii) the vehicle is approaching a traffic jam that is at afull stop at that time and (iv) a fire alert in a building near to thecurrent geographical location of the vehicle.
 19. A collision avoidancesystem of a vehicle, said collision avoidance system comprising: acamera configured to be disposed at a vehicle so as to have a field ofview exterior and forwardly of the vehicle, said camera capturing imagedata; wherein said camera comprises a pixelated imaging array having aplurality of photosensing elements; an image processor operable toprocess image data captured by said camera to determine the presence ofa pedestrian ahead of the vehicle and at or moving towards a path oftravel of the vehicle, wherein said image processor determines adistance to the determined pedestrian and a moving speed of thedetermined pedestrian; wherein said image processor determines a time tocollision based on a determined distance to the pedestrian anddetermined speed of the pedestrian and speed of the vehicle; whereinsaid collision avoidance system is operable to generate an alert to thedriver of the vehicle at a threshold time before the determinedcollision with the pedestrian; wherein, responsive to a parameter, saidcollision avoidance system adjusts the threshold time to generate thealert at an earlier time; wherein said parameter comprises at least oneparameter selected from the group consisting of (i) a vehicle parameterpertaining to the current traction of the vehicle, (ii) an environmentparameter pertaining to the environment in which the vehicle istraveling, (iii) a location parameter pertaining to the geographicalcurrent location of the vehicle, (iv) a location and time parameterpertaining to the current geographical location of the vehicle and aparticular event time associated with that location and (v) a driverattentiveness parameter pertaining to a determined attentiveness of thedriver of the vehicle; wherein said collision avoidance system isoperable to generate a pedestrian alert to the pedestrian responsive toa determination that the pedestrian will be entering the path of travelof the vehicle towards the end of the determined time to collision; andwherein said collision avoidance system, responsive to a determinationthat the determined moving speed of the pedestrian does not changefollowing the pedestrian alert, is operable to apply the brakes of thevehicle to stop the vehicle.
 20. The collision avoidance system of claim19, wherein said collision avoidance system is operable to apply thebrakes of the vehicle to reduce the vehicle speed responsive to adetermination that the pedestrian will be exiting the path of travel ofthe vehicle towards the end of the determined time to collision.